This core will support Projects 1, 2 and 4 requiring expertise in calcium imaging. This core will purchase two major pieces of equipment: 1) a high speed Nipkow dual spinning-disk confocal laser imaging system, and 2) a ratiometric/pressurized blood vessel imaging system system. The high speed Nipkow dual spinning-disk confocal laser imaging system will support projects that need to examine the spread of intracellular and intercellular calcium waves that regulate the membrane potential and contractile activity respectively of the smooth muscle layers of the intact but isolated fundus and colon. Project 2 will examine whether these waves are modified PLB knockout mice compared to their wild type littermates. It will also be determined whether CaMKII inhibitors affect the propagation and duration of these waves. Project 4 will use this apparatus to examine the changes in the spread of intracellular and intercellular calcium waves in the smooth muscle layers from hypertrophied regions of bowel. In addition, Project 4 will use confocal calcium imaging to determine if changes occur to the spread of activity through the neurons of the enteric nervous system. This is possible because [Ca 2+]I is a reliable indicator of action potential dependent changes in the activity of enteric neurons. Project 4 will also use this technology in combination with patch clamp studies to determine if there are changes in the ionic conductances underlying spontaneous Ca 2+ transients (Sparks and Puffs) in isolated smooth muscle cells taken from different regions of bowel with a partial obstruction. Project 1 will utilize the ratiornetric/pressurized vessel imaging system to determine whether Ca 2+ signaling and vascular reactivity are altered in arteries from mdx mice lacking dystrophin compared to their wild type littennates. In addition, single cell Ca 2+ imaging experiments combined with patch clamp techniques will be utilized to provide a detailed understanding of how integrins affect Ca 2+ signaling and currents in isolated vascular smooth muscle cells. Ca2+-permeable (L-type and nonselective) channels will be compared in isolated myocytes from mdx and wildtype mice.